As the field of microfluidics continues to progress, microfluidic devices have become convenient platforms for processing and manipulating micro-objects such as biological cells. Electrokinetic microfluidic devices, such as optically actuated electrokinetic microfluidic devices, offer some desirable capabilities, including the ability to select and manipulate individual micro-objects. Such microfluidic devices require various inputs (e.g., fluid, pressure, vacuum, heat, cooling, light, etc.) to function. Some embodiments of the present invention are directed to systems useful for operating electrokinetic microfluidic devices, including optically actuated electrokinetic microfluidic devices.